Technical Field
The present disclosure relates to a light emitting device that outputs a laser beam through a slit.
Discussion of the Background
Light emitting devices that employ an LED have been used as light sources for signal devices and display of measuring boards, in place of fluorescent lamps and incandescent bulbs. Also, light emitting devices that employ an LED have become increasingly used also for luminaire for general domestic use. Meanwhile, light emitting devices that employ a semiconductor laser diode as a light source have been proposed (for example, see JP 2002-31773A, JP H07-281062A, and JP 4770796B).
Light emitting devices that employ a semiconductor laser diode as a light source are, for example, configured such that laser beam from the light source is irradiated on a diffusion plate to diffuse the laser beam while converting the wavelength by the fluorescent material applied on the diffusion plate, so as to emit visible light. Light sources using a semiconductor laser are small in size and have high power efficiency and can produce high output, in addition to those, they can emit light of clear color via a fluorescent material. Thus, light sources using a semiconductor laser have attracted a great deal of attention as the light sources for future lighting devices.
However, in conventional laser light emitting devices, the laser beam is emitted while controlling the beam diameter of laser beam with a slit provided in the laser light source part. Such a configuration may allow leakage of laser beam from the slit that then propagates as stray light, so that improvement in safety has been demanded.